Just nothing left in New York (4)
I believe the answer is:
only
'just' is the definition.
(I know that just can be written as only)
'nothing left in new york' is the wordplay.
'nothing' becomes 'o' (O resembles 0).
'left' becomes 'l' (common abbreviation).
'in' indicates putting letters inside.
'new york' becomes 'ny'.
'l' put within 'ny' is 'nly'.
'o'+'nly'='ONLY'
(Other definitions for only that I've seen before include "Existing alone with no other, perhaps a child" , ". . . . the Lonely (sung by Roy Orbison)" , "And nothing more; sole" , "Simply" , "Siblingless (child)" .)